At present, portable mobile terminals, cameras, photographic apparatuses and other electronic devices are generally equipped with a plurality of rechargeable batteries. When battery power is used up, the plurality of batteries need to be charged using a charger.
A common charging manner on the market at present is connecting a plurality of rechargeable batteries in parallel, to uniformly charge a rechargeable battery pack in parallel connection. However, the manner has lots of shortcomings. For example, after the rechargeable batteries having different voltage values are connected in parallel, it may result in high voltage batteries discharging to low voltage batteries. Generally the discharge current may be large, and hence is dangerous. In addition, after the plurality of rechargeable batteries are connected in parallel, in the process of charging, it is likely that a charger first charges the low voltage batteries, because the batteries will be fully charged together at the same time. Thus, if a user wants to use a battery fully charged in the process of charging, the user has to wait for a longer time, which is not convenient for use.